Design and evaluation of an automated activated carbon fiber cloth adsorption and recovery system for MEK
The Clean Air Act Amendments (CAAAs) of 1990 have mandated the reduction of emissions of hazardous air pollutants (HAPs) from gas streams. An automated bench-scale activated-carbon fiber-cloth (ACFC) adsorption system was designed and built to simulate the capture and recovery of dilute hazardous air pollutants from gas streams. ACFC has been shown to offer promise as a superior adsorbent to remove volatile organic compounds from gas streams. ACFC has a relatively large micropore volume, narrow pore size distribution, and rapid adsorption kinetics when compared to conventional carbons. ACFC's physical structure also allows convenient and energy efficient electrothermal regeneration. Methyl ethyl ketone (MEK) was used as a representative HAP because of its widespread use, large emission strength and its classification as a HAP. The second-generation system was designed with the ACFC in an annular form resembling a cartridge filter. Total flow rate of the system was 5 lpm and the gas stream contained 1,000 ppmv MEK. Each adsorber contained 30 g of ACFC. The superficial gas velocity through each bed was 1.2 cm/sec, resulting in a 98% reduction in pressure drop over the first-generation system. Elevating the bed temperature by {approximately}10 C was an effective means to reduce competitive adsorption of water vapor for gas streams at 90% relative humidity. The mass of MEK in the saturated bed was calculated to be within 5% of the gravimetrically measured equilibrium isotherm values. Five percent breakthrough times ranged between 11.9 and 12.9 hr. Throughput ratio's of 86.9% were achieved. Electrothermal regeneration times were approximately one hour at 120 watts. Material balances on the adsorption and regeneration cycles showed closure within {approximately} 92%. Capture and recovery of the concentrated MEK is by condensation at {approximately} {minus}50 C.
- Research Organization:
- Univ. of Illinois, Urbana, IL (US)
- OSTI ID:
- 20002184
- Report Number(s):
- CONF-990608--
- Country of Publication:
- United States
- Language:
- English
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